package com.fileutils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Tool {

    public static String md5(String string) {
        byte[] hash;
        try {
            hash = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("Huh, MD5 should be supported?", e);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("Huh, UTF-8 should be supported?", e);
        }

        StringBuilder hex = new StringBuilder(hash.length * 2);
        for (byte b : hash) {
            if ((b & 0xFF) < 0x10)
                hex.append("0");
            hex.append(Integer.toHexString(b & 0xFF));
        }
        return hex.toString();
    }

    /**
     * 加密MD5
     *
     * @return
     */
    public static byte[] md5ToByte(byte[] btData) {
        try {
            // 获得MD5摘要算法的 MessageDigest 对象
            MessageDigest mdInst = MessageDigest.getInstance("MD5");
            // 使用指定的字节更新摘要
            mdInst.update(btData);
            // 获得密文
            return mdInst.digest();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}
